Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B1/00—Preliminary treatment of ores or scrap
  • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
  • C22B1/24—Binding; Briquetting ; Granulating
  • C22B1/2406—Binding; Briquetting ; Granulating pelletizing
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
  • C22B7/02—Working-up flue dust
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B13/00—Obtaining lead
  • C22B13/02—Obtaining lead by dry processes
  • C22B13/025—Recovery from waste materials
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B19/00—Obtaining zinc or zinc oxide
  • C22B19/20—Obtaining zinc otherwise than by distilling
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B19/00—Obtaining zinc or zinc oxide
  • C22B19/30—Obtaining zinc or zinc oxide from metallic residues or scraps
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B19/00—Obtaining zinc or zinc oxide
  • C22B19/34—Obtaining zinc oxide
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B26/00—Obtaining alkali, alkaline earth metals or magnesium
  • C22B26/10—Obtaining alkali metals
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
  • C22B7/001—Dry processes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P10/00—Technologies related to metal processing
  • Y02P10/20—Recycling

Definitions

• EAFD Electric Arc Furnace Dust
• BHD bag house dust
• EAFD Electric Arc Furnace Dust
• Numerous alternatives of pyrometallurgical and hydrometallurgical approaches have been examined for treatment of the EAFD in the last few decades.
• Some commonly used and commercially successful pyrometallurgical process include the Waelz Kiln and similar advanced processes that involve the reduction of EAFD with coke or coal, lime and silica in rotary kiln furnaces.
• these processes are very energy intensive, resulting in high treatment cost, which can make them unfavorable for stand-alone, on-site treatment of dust at most steel mills.
• Hydrometallurgical processing that involves acidic and/or caustic leaching followed by precipitation of metals can be less expensive and energy consumptive, but generates considerable environmentally objectionable effluent and the yield is much lower than that of the pyrometallurgical routes.
• BHD bag house dust
• IEPA International environmental protection agencies
• Zn in BHD is present either in the form of zinc oxide (ZnO) or zinc ferrite (ZnO.Fe203). Removing zinc from a bimetallic compound, such as zinc ferrite (ZnO.Fe203), is more difficult than removing zinc from a mixture of zinc oxide and iron oxide, when zinc and iron are present as discrete compounds.
• the invention in one aspect, relates to a method for recovering a metal oxide from Electric Arc Furnace dust (EAFD), comprising: a) mixing the EAFD comprising zinc oxide or lead oxide with a liquid and a binder to produce an EAFD mixture;
• EAFD Electric Arc Furnace dust
• the invention disclosed here in another aspect relates to a method for recovering zinc from Electric Arc Furnace dust (EAFD), comprising: a) heating the EAFD comprising at least one metal comprising zinc in an inert gas atmosphere at a temperature ranging from 700 °C to 1100 °C; and b) evaporating the least one metal comprising zinc from the EAFD and collecting the at least one metal.
• EAFD Electric Arc Furnace dust
• the invention disclosed here in a further aspect relates to a method for recovering an impurity from Electric Arc Furnace dust (EAFD), comprising: a) heating the EAFD comprising an impurity in an inert gas atmosphere at a temperature ranging from 700 °C to 1100 °C; and b) evaporating the impurity from the EAFD and collecting the impurity.
• EAFD Electric Arc Furnace dust
• the invention disclosed here in yet another aspect relates to a method for recovering iron oxide from Electric Arc Furnace dust (EAFD), comprising: a) heating the EAFD comprising iron oxide and at least one metal in an inert gas atmosphere at a temperature ranging from 700 °C to 1100 °C;
• Figure 1 shows a flow diagram for the Caustic Soda Leaching Process for the extraction of zinc from EAFD of one aspect of the invention herein.
• Figure 2 shows the relationship between the weight loss from a BHD pellet and the temperature at which the pellet is sintered in a 2 atmosphere for one aspect of the invention herein.
• Figure 3 shows the relationship between the weight % content of Zn remaining in a BHD pellet after sintering at various temperatures in a 2 atmosphere for one aspect of the invention herein.
• Figure 4 shows the relationship between the Zn and Pb content of pellets sintered at various temperatures under nitrogen for one aspect of the invention herein.
• Figure 5 shows the Zn and Pb content of vapors extracted from BHD pellets sintered under 2 at various temperatures for one aspect of the invention herein.
• Figure 6 shows the relationship between the weight of Zn removed from a BHD pellet sintered in a 2 atmosphere at various temperatures for one aspect of the invention herein.
• Figure 7 shows the weight loss of Pb, Na, K, and CI from a BHD pellet sintered at various temperatures under 2 for one aspect of the invention herein.
• Ranges can be expressed herein as from “about” one particular value, and/or to "about” another particular value. When such a range is expressed, a further aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about,” it will be understood that the particular value forms a further aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. It is also understood that there are a number of values disclosed herein, and that each value is also herein disclosed as "about” that particular value in addition to the value itself. For example, if the value “10” is disclosed, then “about 10" is also disclosed. It is also understood that each unit between two particular units are also disclosed. For example, if 10 and 15 are disclosed, then 1 1, 12, 13, and 14 are also disclosed.
• references in the specification and concluding claims to parts by weight of a particular element or component in a composition denotes the weight relationship between the element or component and any other elements or components in the composition or article for which a part by weight is expressed.
• X and Y are present at a weight ratio of 2:5, and are present in such ratio regardless of whether additional components are contained in the compound.
• a weight percent (wt. %) of a component is based on the total weight of the formulation or composition in which the component is included.
• the terms “optional” or “optionally” means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.
• compositions disclosed herein have certain functions. Disclosed herein are certain structural requirements for performing the disclosed functions and it is understood that there are a variety of structures that can perform the same function that are related to the disclosed structures, and that these structures will typically achieve the same result.
• green strength testing typically refers to a test that measures the ability of green pellets to remain intact during handling.
• a pellet is dropped a number of times from the height of 30 cm on a flat steel plate until it breaks.
• drop number typically refers to the number of times before it breaks.
• green pellets typically refers to the pellets comprising moisture.
• the term can refer to pellets produced by balling action in a rotating disk or drum comprising moisture before drying or heating.
• the terms “sintered” or “sintering” typically refers to heating to a specific temperature and holding for a specific time in a furnace in certain gaseous or air atmosphere.
• binding typically refers to a compound or composition that aids in binding the powder and formulation of pellets, which can be spherical, in the presence of a specific amount of water.
• binding preparation can be, for example, during balling in a rotating disk or drum.
• inert gas atmosphere typically refers to an atmosphere of non-reactive gases such as nitrogen, argon, xenon, or krypton, and the like.
• electrical arc furnace dust or "EAFD” is a term of art and refers to a solid by-product or material produced from a furnace steelmaking process, and is intended to encompass by-products and materials generated from all steelmaking operation phases and sources, such as, for example, scrap iron furnaces or sponge iron furnaces.
• bag house dust or "BHD” is a term of art and refers to a type of electric arc furnace dust generated in Saudi Arabia, which may, in various aspects, have similar or differing chemical compositions than electric arc furnace dusts produced from different countries.
• the bag house dust can be collected in a bag house, also called a bag house filter.
• the disclosed compositions comprise by-products produced from a steelmaking process.
• the disclosed compositions comprise by-products produced from an electric steelmaking process.
• the by-products comprise electric arc furnace dust (EAFD).
• EAFD electric arc furnace dust
• the electric arc furnace dust (EAFD) comprises EAFD produced in various regions, for example, EAFD from North America or Europe or the Middle East.
• the EAFD comprises EAFD of varying compositions depending on the type of scrap used, type of additives used during the production stage and the type of steel manufacture.
• the EAFD comprises EAFD generated in Saudi Arabia, also referred to as bag house dust (BHD).
• the EAFD comprises unstabilized, untreated EAFD. In a still further aspect, the EAFD comprises stabilized, untreated EAFD. In a yet further aspect, the EAFD comprises treated EAFD. In an even further aspect, the disclosed compositions comprise at least one additional by-product, for example, fly ash, blast furnace slag, or silica fume, or the like.
• An exemplary, non-limiting EAFD comprises one or more components comprising Fe, Zn, Pd, Cr, Cd, Mn, Cu, Si, Ca, Mg, Al, C, Na, or K or a mixture thereof.
• the EAFD comprises Fe in an amount ranging from 10 wt % to 60 wt %, Zn in an amount ranging from 2 wt % to 50 wt %, Pd in an amount ranging from 0.40 wt % to 15.14 wt %, Cr in an amount ranging from 0.2 wt % to 1 1 wt %, Cd in an amount ranging from 0.01 wt % to 0.3 wt %, Mn in an amount ranging from 1 wt % to 5 wt %, Cu in an amount ranging from 0.01 wt % to 0.3 wt %, Si in an amount ranging from 1 wt % to 5 wt %, Ca in an amount ranging from 1 wt % to 25 wt %, Mg in an amount ranging from 1 wt % to 12 wt %, Al in an amount ranging from 0.1 wt % to 4 wt %
• a typical chemical composition of the EAFD is as follows:
• an exemplary, non-limiting composition of EAFD can include 29 wt % of Zn, 0.3 wt % of Cu, 4 wt % of Pb, 0.07 wt % of Cd, 25 wt % of Fe, 4 wt % of CI, 3 wt % of MnO, and 3 wt % of Si0 2 .
• an exemplary, non-limiting EAFD as measured using optical emission via Inductive Coupled Plasma (ICP), X-ray diffractometry (XRD), and M5ssbauer spectroscopy analysis exhibits the following composition: ZnFe 2 0 4 , Fe 3 0 4 , MgFe 2 0 4 , FeCr 2 0 4 , CaO 15Fe 2. s 5 0 4 , MgO, Mn 3 0 4 , S1O2, and ZnO.
• most of the elements in the EAFD are in the oxide form.
• the disclosed methods and compositions comprising EAFD provide numerous environmental advantages.
• the use of EAFD according to the present invention provides an effective means of EAFD disposal.
• the disclosed methods and compositions, by utilizing EAFD reduce potential environment problems associated with EAFD disposal.
• the disclosed methods and compositions eliminate the need to dispose of EAFD in a landfill.
• the reduction in EAFD disposal frees landfill space.
• the disclosed methods and compositions utilize untreated EAFD, thereby avoiding the cost associated with pretreatment of EAFD.
• the invention comprises a method for preparing Electric Arc Furnace dust (EAFD) for metal recovery, comprising: a) mixing the EAFD comprising zinc oxide or lead oxide, or a mixture of both with a liquid and a binder to produce an EAFD mixture; b) producing a shaped EAFD pellet; and c) drying the shaped EAFD pellet.
• EAFD Electric Arc Furnace dust
• the method for preparing EAFD for metal recovery can use methods, techniques, or compositions from the other disclosed methods.
• the shaped EAFD pellet can be produced in a rotating balling disc or a drum.
• the zinc oxide or lead oxide, or a mixture of both can be present in an amount from about 0.01 wt% to about 50 wt%, based on the total weight of the EAFD, including exemplary values of 0.40 wt%, 0.50 wt%, 2 wt%, 4 wt%, 6 wt%, 8 wt%, 10 wt%, 13 wt%, 15 wt%, 17 wt%, 20 wt%, 23 wt%, 25 wt%, 27 wt%, 30 wt%, 33 wt%, 35 wt%, 37 wt%, 40 wt%, 43 wt%, 45 wt%, 46 wt%, and 48 wt%.
• the zinc oxide or lead oxide, or a mixture of both can be present in a range derived from any two of the above listed exemplary wt%.
• the zinc oxide or lead oxide, or a mixture of both can be present in an amount from about 0.40 wt% to about 17 wt%.
• the EAFD is BHD.
• the EAFD dust can come from a steel plant or other source.
• the EAFD can be dried in the sun to gain a sufficient strength so that these pellets can be transported.
• the liquid comprises water.
• the liquid can be present in an amount from about 6.0 wt% to about 12 wt%, based on the total weight of the EAFD mixture, which includes the binder and liquid, including exemplary values of 6.0 wt%, 8.0 wt%, 10 wt%, and 12 wt%.
• the liquid can be present in a range derived from any two of the above listed exemplary wt%.
• the liquid can be present in an amount from about 8.0 wt% to about 10.0 wt%, 6 wt% to 12 wt %, or 6 wt % to 8 wt %.
• the binder comprises carbon, burnt lime, bentonite, or molasses, or a mixture thereof. In a still further aspect, the binder is bentonite. In a yet further aspect, the binder is molasses.
• the binder can be present in an amount from about 0.01 wt% to about 5.0 wt%, based on the total weight of the EAFD mixture, which includes the binder and liquid, including the exemplary values of 0.25 wt%, 0.50 wt %, 0.75 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, and 4.5 wt%.
• the binder can be present in a range derived from any two of the above listed exemplary wt%.
• the binder can be present in an amount from about 0.25 wt% to about 1.0 wt%.
• the binder comprises carbon in an amount from about 10 wt% to about 25 wt% based on the total weight of the binder, including the exemplary values of 12 wt%, 14 wt%, 16 wt%, 18 wt%, 20 wt%, 22 wt%, and 24 wt%.
• the binder comprises carbon in a range derived from any two of the above listed exemplary wt%.
• the binder can comprise carbon in an amount from about 16 wt% to about 18 wt% based on the total weight of the binder.
• the binder comprises molasses in an amount from about 0.01 wt% to about 5.0 wt%, based on the total weight of the EAFD mixture, including the exemplary values of 0.5 wt%, 1 wt %, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, and 4.5 wt%.
• the binder comprises molasses in a range derived from any two of the above listed exemplary wt%.
• the binder can comprise molasses in an amount from about 1 wt% to about 2 wt%.
• the binder is molasses.
• the bentonite which is a trade name of a binder comprising sodium potassium silicate, is used in the binder herein.
• the binder can comprise bentonite in an amount ranging from 0 wt % to 4.5 wt %, based on the total weight of the EAFD mixture, which includes the binder and liquid, including exemplary values 0.5 wt %, 1 wt %, 1.5 wt %, 2 wt %, 2.5 wt %, 3 wt %, 3.5 wt %, and 4 wt %.
• the binder comprises bentonite in a range derived from any two of the above listed exemplary wt %.
• the binder can comprise bentonite in a range from 0.5 wt % to 4 wt % based on the total weight of the EAFD.
• the binder is bentonite.
• the EAFD can be mixed with the liquid and binder using conventional methods such as with an intensive mixer, such as a ROB Erich mixer or any other mixing equipment.
• an intensive mixer such as a ROB Erich mixer or any other mixing equipment.
• the method comprises producing an EAFD mixture.
• the EAFD mixture is a homogeneous composition.
• the EAFD pellet can be produced using any conventional method to produce a pellet, such as with a pan pelletizer or a drum pelletizer.
• forming a pellet can be desirable as a form to contain the dust in a leach-proof matrix for storing and disposing the EAFD.
• the EAFD pellet can be dried using any conventional method for drying, such as drying in the sun for a period of 1-4 days or heating in a drying oven.
• the average pellet size can range from about 7 mm to 18 mm, including exemplary values of 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, and 17 mm.
• the average pellet size can be in a range derived from any two of the above listed exemplary values. For example, the average pellet size can range from 8 mm to 17 mm.
• the pellet is a spherical shape. In another aspect, the pellet can be any conventional pellet shape.
• the pellet is produced using conventional methods.
• the pelletizing comprises the steps of grinding, sieving, mixing, agglomeration, binder optimization, and sintering.
• the pelletizing uses a R02 Elrich mixer followed by pelletization on a disc pelletizer to produce the pellets.
• the pellet has improved properties in physical, mechanical, chemical, and metallurgical properties.
• the pellet can be used in the method disclosed herein for recovering zinc or zinc oxide from EAFD.
• the pellet can be used as a way to transport the EAFD for metal recovery.
• the pellet can be used in the method disclosed herein for recovering lead, chlorine, sodium, or potassium, or a mixture thereof.
• the pellet can be used in the method disclosed herein for recovering iron oxide.
• the invention comprises a method for recovering zinc from Electric Arc Furnace dust (EAFD), comprising: a) heating the EAFD comprising at least one metal comprising zinc in an inert gas atmosphere at a temperature ranging from 700 °C to 1100 °C; and b) evaporating the at least one metal comprising zinc from the EAFD and collecting the at least one metal.
• EAFD Electric Arc Furnace dust
• FIG. 1 shows a flow diagram for the Caustic Soda Leaching Process for the extraction of zinc from EAFD of one aspect of the invention herein.
• Figure 1 shows the inventive process for recovering the zinc using heating and evaporation.
• the zinc comprises zinc metal, zinc oxide or a complex of zinc and another metal oxide, or a mixture thereof.
• the zinc comprises zinc oxide.
• the zinc comprises a complex of zinc and a metal oxide.
• the metal oxide of the complex comprises iron oxide.
• the complex of zinc and iron oxide can be zinc ferrite (ZnO Fe 2 0 3 , franklinite).
• the zinc can comprise approximately 50 wt% in the zinc ferrite form based on the total weight of the zinc. The removal of the zinc from the EAFD can reduce the environmental liability and/or can create a value-added product by collecting the zinc.
• the zinc can be present in an amount from about 0.01 wt% to about 50 wt%, based on the total weight of the EAFD, including the exemplary values of including exemplary values of 0.40 wt%, 0.50 wt%, 2 wt%, 4 wt%, 6 wt%, 8 wt%, 10 wt%, 13 wt%, 15 wt%, 17 wt%, 20 wt%, 23 wt%, 25 wt%, 27 wt%, 30 wt%, 33 wt%, 35 wt%, 37 wt%, 40 wt%, 43 wt%, 45 wt%, 46 wt%, and 48 wt%.
• the zinc can be present in a range derived from any two of the above listed exemplary wt%.
• the zinc can be present in an amount from about 2.0 wt% to about 46 wt%
• the EAFD is BHD.
• the EAFD can come from a steel plant or other source.
• the EAFD is in the form of a pellet.
• the average EAFD pellet size can range from about 7 mm to 18 mm, including exemplary values of 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, and 17 mm.
• the average pellet size can be in a range derived from any two of the above listed exemplary values.
• the average pellet size can range from 8 mm to 17 mm.
• the inert gas comprises N 2 , Ar, CO, or H2, or a mixture thereof.
• the inert gas comprises Ar, CO, or H2, or a mixture thereof.
• the inert gas comprises CO or H2, or a mixture thereof.
• the inert gas is N 2 .
• the inert gas is Ar.
• the inert gas is CO.
• the inert gas is H2.
• the EAFD can be heated using a Static Reduction Reactor or any other suitable heating device.
• the Static Reduction Reactor further comprises a) a system to supply and regulate the gases, b) a reductible tube of heat resistant steel, c) a weighing device to determine the oxygen loss at regular intervals, d) an electrically heated furnace to heat the test portion to the specified
• a chart recorder to record the weight loss and a control panel to control the flow and pressure of gas supplied.
• the EAFD can be heated at a temperature of from about 700°C to about 1100°C, including the exemplary values of 750°C, 800°C, 900°C, 1000°C, and 1050°C.
• the EAFD can be heated in a range derived from any two of the above listed exemplary temperatures.
• the EAFD pellets can be heated at a temperature from about 750°C to about 1050°C.
• the at least one metal comprising zinc was evaporated until there is no more or substantially no more loss of weight from the EAFD source.
• the zinc is evaporated and exits with at least one exhaust gas.
• the gases can be cooled and can be filtered in a cloth filter to collect a powder.
• the powder can comprise Zn and/or ZnO.
• the powder is filtered from the gas which can comprise Pb, Na, and/or K.
• the Pb, Na, and/or K can be in a compound with chlorine.
• the Na or K in the form of NaCl or KC1, respectively can be dissolved in water and removed.
• the invention further comprises re-oxidizing the zinc to form zinc oxide and collecting the zinc oxide.
• the invention comprises a method for recovering an impurity from Electric Arc Furnace dust (EAFD), comprising: a) heating the EAFD comprising an impurity in an inert gas atmosphere at a temperature ranging from 700 °C to 1100 °C; and b) evaporating the impurity from the EAFD and collecting the impurity.
• EAFD Electric Arc Furnace dust
• the method for recovering an impurity from EAFD can use methods, techniques, or compositions from the other disclosed methods.
• the impurity comprises lead, chlorine, sodium, or potassium, or a mixture thereof.
• the impurity comprises lead, chlorine, or sodium, or a mixture thereof.
• the impurity comprises lead or chlorine, or a mixture thereof.
• the impurity is lead.
• the impurity is chlorine.
• the impurity is sodium.
• the impurity is potassium. The removal of the impurity from EAFD can reduce the environmental liability and/or can create a value-added product by collecting the metal.
• the impurity can be present in an amount from about 0.01 wt% to about 20 wt%, based on the total weight of the EAFD, including the exemplary values of 0.35 wt%, 0.40 wt%, 0.50 wt%, 1.8 wt%, 3.0 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 1 1 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, and 19 wt%.
• the impurity can be present in a range derived from any two of the above listed exemplary wt%.
• the impurity can be present in an amount from about 0.5 wt% to about 1.8 wt%.
• the impurity further comprises chromium, cadmium, manganese, copper, silicon, calcium, magnesium, aluminum, carbon, or sulfur, or a mixture thereof. In a still further aspect, the impurity further comprises chromium, cadmium, manganese, copper, silicon, calcium, or magnesium, or a mixture thereof. In yet a further aspect, the impurity further comprises chromium, cadmium, manganese, silicon, carbon, or magnesium, or a mixture thereof. In an even further aspect, the impurity further comprises calcium or magnesium, or a mixture thereof. In an even further aspect, the impurity further comprises calcium.
• the EAFD is BHD. In another aspect, the EAFD is in the form of a pellet.
• the average EAFD pellet size can range from about 7 mm to 18 mm, including exemplary values of 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, and 17 mm. In a still further aspect, the average pellet size can be in a range derived from any two of the above listed exemplary values. For example, the average pellet size can range from 8 mm to 17 mm.
• the inert gas comprises N 2 , Ar, CO, or H 2 , or a mixture thereof.
• the inert gas comprises Ar, CO, or H2, or a mixture thereof.
• the inert gas comprises CO or H2, or a mixture thereof.
• the inert gas is N 2 .
• the inert gas is Ar.
• the inert gas is CO.
• the inert gas is H2.
• the EAFD can be heated using a Static Reduction Reactor.
• the Static Reduction Reactor further comprises a) a system to supply and regulate the gases, b) a reductible tube of heat resistant steel, c) a weighing device to determine the oxygen loss at regular intervals, d) an electrically heated furnace to heat the test portion to the specified temperature, and/or e) a chart recorder to record the weight loss and control panel to control the flow and pressure of gas supplied.
• the EAFD pellet can be heated at a temperature from about 700 C to about 1 lOO C, including the exemplary values of 750 C, 800 C, 900 C, lOOO C, and 1050 C.
• the EAFD pellet can be heated in a range derived from any two of the above listed exemplary temperatures.
• the EAFD pellet can be heated at a temperature from about 750 C to about 1050 C.
• the metal is evaporated under inert atmosphere.
• the at least one metal is evaporated until there is no more loss of weight.
• the evaporated impurity is collected by cooling it to form a solid powder condensate and filtering and collecting in a bag filter.
• the method for recovering iron oxide from EAFD can use methods, techniques, or compositions from the other disclosed methods.
• the iron can be present as iron oxide or as a complex of zinc and iron oxide, or a mixture thereof. In a still further aspect, the iron can be present as iron oxide. In yet a further aspect, the iron can be present as a complex of zinc and iron oxide. The removal of the metal from the EAFD can reduce the environmental liability and/or can create a value-added product by collecting the iron oxide.
• the metal further comprises zinc, lead, chromium, cadmium, manganese, copper, silicon, calcium, magnesium, aluminum, carbon, sulfur, sodium, potassium, or chlorine, or a mixture thereof.
• the metal further comprises zinc, lead, chromium, cadmium, manganese, copper, silicon, calcium, magnesium, sodium, potassium, or chlorine, or a mixture thereof.
• the metal further comprises zinc, lead, chromium, cadmium, manganese, silicon, carbon, magnesium, sodium, potassium, or chlorine, or a mixture thereof.
• the metal further comprises zinc, lead, sodium, potassium, or chlorine, or a mixture thereof.
• the metal further comprises zinc, or lead, or a mixture thereof.
• the metal further comprises zinc, or lead, or a mixture thereof.
• the metal further comprises zinc.
• the metal further comprises lead.
• the iron can be present in an amount from about 0.01 wt% to about 68 wt%, based on the total weight of the EAFD, including the exemplary values of including exemplary values of 0.40 wt%, 0.50 wt%, 2 wt%, 4 wt%, 6 wt%, 8 wt%, 10 wt%, 13 wt%, 15 wt%, 17 wt%, 20 wt%, 23 wt%, 25 wt%, 27 wt%, 30 wt%, 33 wt%, 35 wt%, 37 wt%, 40 wt%, 43 wt%, 45 wt%, 46 wt%, 48 wt%, 50 wt%, 52 wt%, 54 wt%, 56 wt%, 58 wt%, 60 wt%, 62 wt%, 64 wt%, and 66 wt%
• the other metals detailed above can be present in an amount from about 0.01 wt% to about 68 wt%, based on the total weight of the EAFD, including the exemplary values of including exemplary values of 0.2 wt%, 0.3 wt%, 0.40 wt%, 0.50 wt%, 2 wt%, 4 wt%, 6 wt%, 8 wt%, 10 wt%, 13 wt%, 15 wt%, 17 wt%, 20 wt%, 23 wt%, 25 wt%, 27 wt%, 30 wt%, 33 wt%, 35 wt%, 37 wt%, 40 wt%, 43 wt%, 45 wt%, 46 wt%, 48 wt%, 50 wt%, 52 wt%, 54 wt%, 56 wt%, 58 wt%, 60 wt%, 62
• the other metals detailed above can be present in a range derived from any two of the above listed exemplary wt%.
• the other metals detailed above can be present in an amount from about 0.01 wt% to about 0.3 wt%.
• the EAFD is BHD. In another aspect, the EAFD is in the form of a pellet.
• the average pellet size can range from about 7 mm to 18 mm, including exemplary values of 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, and 17 mm.
• the average pellet size can be in a range derived from any two of the above listed exemplary values.
• the average pellet size can range from 8 mm to 17 mm.
• the inert gas comprises 2 or Ar or a mixture thereof.
• the inert gas is N 2 .
• the inert gas is Ar.
• the EAFD can be heated using a Static Reduction Reactor.
• the Static Reduction Reactor further comprises a) a system to supply and regulate the gases, b) a reductible tube of heat resistant steel, c) a weighing device to determine the oxygen loss at regular intervals, d) an electrically heated furnace to heat the test portion to the specified temperature, and/or e) a chart recorder to record the weight loss and control panel to control the flow and pressure of gas supplied.
• the EAFD can be heated at a temperature from about 700°C to about 1 100°C, including the exemplary values of 750°C, 800°C, 900°C, 1000°C, and 1050°C.
• the EAFD can be heated in a range derived from any two of the above listed exemplary temperatures.
• the EAFD can be heated at a temperature from about 750°C to about 1050°C.
• the at least one metal comprises zinc, zinc oxide, and/or zinc ferrite.
• the zinc oxide and/or zinc ferrite can be dissociated.
• the zinc is evaporated.
• the iron oxide is separated from the oxide of calcium, magnesium, silicon, and/or aluminum.
• the oxide of calcium, magnesium, silicon, and/or aluminum is left behind in the pellet.
• the residual pellet comprises iron oxide and/or the oxide of calcium, silicon, aluminum, and/or magnesium.
• the pellet can be collected from the sintering tube after cooling.
• the iron oxide is present in a purity of 45 wt% to 80 wt% based on the total weight of the EAFD, including exemplary values of 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, and 75 wt%.
• the iron oxide is present in a purity derived from any two of the above listed exemplary wt%.
• the iron oxide is present in a purity of 55 wt% to 70 wt%.
• compositions and methods include at least the following aspects.
• a method for preparing Electric Arc Furnace dust (EAFD) for metal recovery comprising: a) mixing the EAFD comprising zinc oxide or lead oxide, or a mixture of both, with a liquid and a binder to produce an EAFD mixture;
• Aspect 2 The method according to aspect 1, wherein the EAFD is Bag House Dust (BHD).
• BHD Bag House Dust
• Aspect 3 The method according to any one of aspects 1-2, wherein the metal oxide is zinc oxide.
• Aspect 4 The method according to any one of aspects 1-3, wherein the metal oxide is lead oxide.
• Aspect 5 The method according to any one of aspects 1-4, wherein the liquid is water.
• Aspect 6 The method according to any one of aspects 1-5, wherein the liquid is present in an amount from about 6.0 wt% to 12.0 wt%, based on the total weight of the EAFD mixture.
• Aspect 7 The method according to any one of aspects 1-6, wherein the liquid is present in amount from about 6.0 wt% to 10.0 wt%, based on the total weight of the EAFD mixture.
• Aspect 8 The method according to any one of aspects 1-7, wherein the liquid is present in amount from about 6.0 wt% to 8.0 wt%, based on the total weight of the EAFD mixture.
• Aspect 9 The method according to any one of aspects 1-8, wherein the binder is present in an amount from about 0.01 wt% to about 5.0 wt%, based on the total weight of the EAFD mixture.
• Aspect 10 The method according to any one of aspects 1-9, wherein the binder is present in an amount of about 0.25 wt%, based on the total weight of the EAFD mixture.
• Aspect 11 The method according to any one of aspects 1-10, wherein the binder is present in an amount of about 0.50 wt%, based on the total weight of the EAFD mixture.
• Aspect 12 The method according to any one of aspects 1-11, wherein the binder is present in an amount of about 0.75 wt%, based on the total weight of the EAFD mixture.
• Aspect 13 The method according to any one of aspect 1-12, wherein the binder is present in an amount of about 1.00 wt%, based on the total weight of the EAFD mixture.
• Aspect 14 The method according to any one of aspects 1-13, wherein the binder is present in an amount of about 1.50 wt%, based on the total weight of the EAFD mixture.
• Aspect 15 The method according to any one of aspects 1-14, wherein the binder is present in an amount of about 2.00 wt%, based on the total weight of the EAFD mixture.
• Aspect 16 The method according to any one of aspects 1-15, wherein the average pellet size is from about 7.0 to 18 mm.
• a method for recovering zinc from Electric Arc Furnace dust comprising: a) heating the EAFD comprising at least one metal comprising zinc in an inert gas atmosphere at a temperature ranging from 700 °C to 1100 °C; and b) evaporating the at least one metal comprising zinc from the EAFD and collecting the at least one metal.
• EAFD Electric Arc Furnace dust
• Aspect 18 The method according to aspect 17, wherein the at least one metal is zinc.
• Aspect 19 The method according to any one of aspects 17-18, wherein the EAFD is Bag House Dust (BHD).
• BHD Bag House Dust
• Aspect 20 The method according to any one of aspects 17-19, wherein the inert gas comprises 2 or Ar, or a mixture thereof.
• Aspect 21 The method according to any one of aspects 17-20, wherein the inert gas comprises Ar.
• Aspect 22 The method according to any one of aspects 17-21, wherein the inert gas is N 2 .
• Aspect 23 The method according to any one of aspects 17-22, wherein the method comprises re-oxidizing the zinc to form zinc oxide and collecting the zinc oxide.
• Aspect 24 The method according to any one of aspects 17-23, wherein the EAFD is a pellet.
• a method for recovering an impurity from Electric Arc Furnace dust comprising: a) heating the EAFD comprising an impurity in an inert gas atmosphere at a temperature ranging from 700 °C to 1100 °C; and b) evaporating the impurity from the EAFD and collecting the impurity.
• EAFD Electric Arc Furnace dust
• Aspect 26 The method according to aspect 25, wherein the EAFD is Bag House Dust (BHD).
• BHD Bag House Dust
• Aspect 27 The method according to any one of aspects 25-26, wherein EAFD is in the form of a pellet.
• Aspect 28 The method according to any one of aspects 25-27, wherein the impurity comprises lead, chlorine, or sodium, or a mixture thereof.
• Aspect 29 The method according to any one of aspects 25-28, wherein the impurity comprises lead, or chlorine, or a mixture thereof.
• Aspect 30 The method according to any one of aspects 25-29, wherein the impurity comprises lead.
• Aspect 31 The method according to any one of aspects 25-30, wherein the impurity comprises chlorine.
• Aspect 32 The method according to any one of aspects 25-31, wherein the impurity comprises sodium.
• Aspect 33 The method according to any one of aspects 25-32, wherein the impurity comprises potassium.
• Aspect 34 The method according to any one of aspects 25-33, wherein the inert gas comprises 2 or Ar, or a mixture thereof.
• Aspect 35 The method according to any one of aspects 25-34, wherein the inert gas is N 2 .
• Aspect 36 The method according to any one of aspects 25-35, wherein the inert gas is Ar.
• Aspect 37 The method according to any one of aspects 28-36, wherein the method comprises re-oxidizing the lead to form lead oxide and collecting the lead oxide.
• Aspect 38 The method according to any one of aspects 25-37, wherein the average pellet size is from about 7.0 to 18 mm.
• a method for recovering iron oxide from Electric Arc Furnace dust comprising: a) heating the EAFD comprising iron oxide and at least one metal in an inert gas atmosphere at a temperature ranging from 700 °C to 1100 °C; and b) separating the iron oxide by evaporating the at least one metal from the EAFD and leaving the iron oxide as a residue.
• EAFD Electric Arc Furnace dust
• Aspect 40 The method according to aspect 39, wherein the EAFD is Bag House Dust (BHD).
• BHD Bag House Dust
• Aspect 41 The method according to any one of aspects 39-40, wherein the inert gas comprises 2 or Ar, or a mixture thereof.
• Aspect 42 The method according to any one of aspects 39-41, wherein the inert gas is N 2 .
• Aspect 43 The method according to any one of aspects 39-42, wherein the inert gas is Ar.
• Aspect 44 The method according to any one of aspects 39-43, EAFD is in the form of a pellet.
• Aspect 45 The method according to any one of aspects 39-44, wherein the at least one metal comprises zinc, lead, chromium, cadmium, manganese, copper, silicon, calcium, magnesium, aluminum, carbon, sulfur, sodium, potassium, or chlorine, or a mixture thereof.
• Pelletizing included the steps of grinding and sieving, mixing, agglomeration, green strength testing, and binder optimization; evaluation included sintering, and testing of the pellets compressive strength after heating.
• BHD contained more than 95% of particle size less than 90 microns, which did not require any further grinding, was used. Only sieving was conducted to remove the dust fraction > 90 microns. Bentonite and burnt lime were used as binders. The optimum binder addition was determined for each of the mixtures. All the samples were pelletized and evaluated to determine the physical and metallurgical properties of the pellets produced.
• Binder additions of 0.25, 0.50, 0. 75, 1.00, 1.5 and 2 wt % binder, based on the total EAFD weight, respectively were added to determine the optimum binder content.
• Batches (3-5 kg) of each sample were premixed with the different binder additives in an R02 Elrich mixer followed by pelletization on a disc pelletizer to produce pellets with size range of 09 to 16 mm.
• PELLETS PROPERTIES PELLETS PROPERTIES
• Table 1 below shows the Drop Number of BHD pellets. All the green pellets were optimized to demonstrate a Drop Number of more than 4. A minimum of 3 drops are required for pellets to be transported for sintering in a commercial pelletizing/sintering plant.
• Table 1 Typical drop number of BHD green EAFD pellets with varying contents of moisture and binder after optimizing drop number
• the sintering tube was made of non-scaling, heat resistance metal to withstand temperatures of higher than 1100 °C.
• the wire grid was mounted in the reduction tube at the quarter depth from the bottom of the retort, for supporting the raw material test portion.
• the weight of the sample used for each sintering test was 500 g ⁇ 2 g.
• the weighing device with this equipment was capable of weighing the load to an accuracy of 1 g.
• the weighing device was checked for sensitivity at regular intervals.
• Each sample containing 500g of dried BHD pellets was then heated at 700 - 1100 °C in an atmosphere of N 2 , to study the effects of this inert gas on zinc removal.
• the samples were heated until there is no more loss of weight.
• the samples were left in the furnace to cool down to room temperature.
• the residual pellets and vapor condensates were analyzed for chemical composition using XRF, C & S Analyzers and phases using XRD techniques.
• Figure 3 shows the comparison of Zn content of BHD pellets sintered in 2 atmosphere at various temperatures.
• Figure 4 is a graph depicting the Zn and Pb content of pellets sintered under a nitrogen atmosphere at various temperatures.
• Figure 5 gives the Zn and Pb content of vapor condensate extracted from BHD pellets by sintering in nitrogen at various temperatures.
• Figure 6 gives the weight % of Zn removed from BHD pellets during sintering in a 2 atmosphere at different temperatures. The values were summarized in Table 3 below. As shown, 85% and 97% of the Zn could be removed from BHD at temperatures 1000 °C and 1100 °C in a 2 atmosphere, respectively. However, oxygen in iron oxide could not be removed with N 2 . Hence, the residue comprises iron in the form of iron oxide. The chemical analysis of the vapor condensate showed that the total zinc content was in the form of metallic Zn and ZnO, and it was mixed with PbO, Na, K, and CI. Further hydrometallurgical treatment was required to separate all these constituents.

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